Can Arctic Char adapt to a changing North?

Arctic Char (Salvelinus alpinus), one of the most interesting freshwater fish species in Canada, is an important cultural, subsistence, and economic resource for inhabitants of Canada’s Arctic. Arctic Char are prized for their tasty flesh and have provided an important food resource for Inuit communities for centuries. Historically, harvesting occurred at stream mouths, in shallow streams, or below small waterfalls during char migrations from sea to freshwater. The Canadian Arctic Expedition (1913 to 1916) observed large harvests of char by the Copper Inuit at Bernard Harbour (Nulahugyuk) in the Coronation Gulf. Inuit-constructed rock weirs were observed near the mouth of Nulahugyuk Creek to direct char into rock traps where they could be easily speared using a ‘kakivak’.

The extent to which small Arctic streams, such as Nulahugyuk Creek, are important for present day char populations is poorly understood. It is known that char are limited to specific freshwater habitats and the successful journey to and through the freshwater habitat is vulnerable to changes in water levels. The timing of migrations would be expected to be specific to, and synced with, local climates and flow regimes.

The char population at Bernard Harbour is particularly unique in that the population relies on a small watercourse to connect the food-rich marine environment to the freshwater spawning and wintering lake (Hingittok Lake). The spawning population migrates from the ocean to the lake in early summer rather than continuing to forage in the ocean until late summer like other populations in the region. Adults then spawn later that fall, overwinter in the lake, and return to the ocean in spring when the creek is ice-free and flows are highest. They do not spawn every year, and during a non-spawning year, the Nulahugyuk Creek char overwinter in the Coppermine River, as discovered using information collected during a tagging study by the Kugluktuk Hunters and Trappers Organization.

Why would spawning adults not use the predictable conditions in the nearby Coppermine River to access spawning lakes instead of Nulahugyuk Creek? The simple answer could be that the reproductive benefits of Hingittok Lake outweigh the potential risks of failing to reach the lake or dying on their journey. However, the char run at Bernard Harbour has declined markedly since the 1980s, according to residents of the nearby Hamlet of Kugluktuk. Low returns have been particularly evident in recent years and are thought to be the result of several related factors, including climate change and resulting low water in the creek. A reduction in flow, for example, exposes barriers, increases the likelihood of mortality by stranding, increases exposure to the elements and predators such as gulls and bears, and causes various physiological stresses. This is the reality for char struggling to navigate Nulahugyuk Creek, and has been the subject of recent investigations by a unique partnership led by the local community (Kugluktuk Hunters and Trappers Organization), private sector, and industry in an effort to provide a ‘made in the North’ solution to conserve this historically significant fishery.

The close proximity of historical Inuit settlements to char waters in the North highlights an important connection to the land that remains strong today. Indeed, both Traditional Knowledge and science describe char as a remarkably adaptable species, inhabiting waters farther north than any other freshwater fish, and displaying diverse behaviours, body forms, and habitat selection across their range. As for other species in the North, climate change means new challenges for migrating char, and although some local populations may adapt to such change, others may not.

The North is one of the final frontiers in biology in Canada where new expeditions will certainly yield new discoveries. Research in remote locations in the Arctic brings with it logistical and financial challenges; with perseverance, as the Bernard Harbour char are demonstrating, inhospitable conditions and long distances can be overcome. Efforts are underway to combine current data with historical records and Traditional Knowledge, which will hopefully lead to successful management and conservation of this remarkable species. Cam Stevens